关键词: 杏仁；有机酸；氨基酸；营养品质；主成分分析；聚类分析

Abstract: The organic acids and amino acids of 88 samples of apricot seed kernels from southern Xinjiang were determined by gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). The results showed that the content of total organic acids ranged from 23.75 to 11 446.19 μg/g, malic acid comprising the highest proportion (46.66%) of the total, followed by oxalic acid (14.67%) and citric acid (12.06%), and gluconic acid accounting for the lowest proportion (0.05%). Oleic acid was the predominant unsaturated fatty acid, accounting for 59.91% of the total fatty acids; and palmitic acid was the major saturated fatty acids, accounting for 12.57% of the total fatty acids. A total of 15 amino acids were detected in all samples, the total amino acid content was 79.55–4 464.17 μg/g, and the essential amino acid content was 21.62–1 248.35 μg/g. The results of principal component analysis (PCA) showed that the cumulative variance contribution rate of the first eight principal components for acid compounds was 85.05%, and malic acid, citric acid, valine, threonine, glutamine, serine, oleic acid, linoleic acid, succinic acid and acetic acid important indexes for evaluating the quality of apricot seed kernels. The samples were clustered into four groups based on the contents of 31 polar metabolites. The first group consisted of eight samples, which were abundant in malate, fatty acid and glutamate. The second group included 77 samples, which were moderate in malic acid and fatty acid and low in amino acids. The third group included ‘Zao Da You Xing’ and ‘Lopu 2’, which had high succinic acid content, moderate fatty acid content and low amino acid content. The final group included ‘Wan Shu Hei Ye Xing’, characterized by the highest succinic acid content, low fatty acid content and high amino acid content.

Key words: apricot seed kernels; organic acid; amino acid; nutritional quality; principal component analysis; clustering analysis